The invention refers to a roller shutter rod of stable shape, which consists of an aluminium strip roll-formed into a hollow section, and a method for the manufacture of such a dimensionally stable roller shutter member.
A roller shutter rod of stable shape, which features in the centerline of the hollow section a reinforcing part, is known from EP 00 75768. Said reinforcing part consists of a PVC insert, which can be additionally reinforced during manufacture by the extrusion process by means of a metallic core. The finished roller shutter rod of plastic material features disadvantages at weathering exposure, especially at exposure to solar radiation and low temperatures. Under these conditions, there can result an embrittlement of the plastic material, and after a longer exposure also a decolourizing of the outer coating. In addition, the manufacturing procedure is extremely time-consumed and expensive.
A roller shutter rod is known from the German registered utility patent G 8907445, which is roll-formed with the formation of connecting areas and walls from a plastic-coated aluminium strip. In this known roller shutter rod the coatings of the walls feature differing coating weights per unit area, so that it is possible to achieve a dampening of the vibrations of the section, and thus a reduction of sound emission.
Another roller shutter rod is described in the European patent application EP 03 65 908, which is roll-formed from a one-side coated aluminium strip into a hollow section, a double-layer plastic coating being formed in the area of the connecting areas, which ensures a damping of the sound radiated by the roller shutter, as the acoustic decoupling of the aluminium surfaces prevents the transmission of sound between same.
The invention is based on the task of realizing a roller shutter rod of stable shape, featuring improved bending strength and durability, without reducing the acoustic damping properties. The task of the invention is also the specification of a manufacturing method for such a roller shutter rod of stable shape with high bending strength and durability.